Jack-screw.



"' 668663- Patented Feb; 2s', Ism.' F.H-.--f-sT||.|.-,MAN. J-AcK scnEw.(Application Bled (No Model.)

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UNITED STATES PATENT OFFICE.

FRANCIS H. STILLMAN, OF BROOKLYN, NEW YORK.

JACK-SCREW.

SPECIFICATION forming part of Letters Patent No. 668,663, dated February26, 1901. Application iiled July 13. 1899. Serial No. 723,664. (Nomodel.)

To all whom it may concern:

Be it known that I, FRANCIS H. STILLMAN, a citizen of the United States,and a resident of the borough of Brooklyn, in the county of Kings, inthe city and State of NewYork, have invented a certain new and usefulImprovement in J ack-Screws, of which the following is a full, clear,and exact description, referused.

y showing the standard in its shortest form;

Figs. 3 and 4, side and sectional elevations showing a taller standard,and Fig. 5 is a plan of one of the standards.

Similar reference-numerals designate like parts in different views.

This jack or set of jacks is especially designed to be used instead ofblocks to aid in adjusting and properly supporting pieces of machineryand other objects on a machinesuch, for example, as a planing-machine ordrilling-machine-to the action of which the objects are to be subjected;but this use of the invention is only one of many to which it isapplicable, as will be apparent to any one who is familiar with thevarious operations commonly performed in a machine-shop. The' jack iscomposed of three parts, these being a standard., a screw, and a nut.The standard may have either of the forms shown in the drawings or aform 4differing from either of these in height. Figs. l and 2 show thefull size of the jack with the short standard l, and Figs. 3 and 4 itsfull size with the taller standardl l. The standard is a blockconsisting of the base l0 or l0', or a similar base, and the shorthexagonal prism 11, and it contains the square hole l2., It ispreferably a steel casting. The screw 2 or the longer screw 2 isprovided with the square head 20, which its loosely in the hole in thestandard and is movable up and down, but

cannot be turned therein. The nut 3 engages and supports the screw, then'ut bearing on the top of the standard.

When the jack is operated, the standard is held with a wrench engagingthe prism l1 to prevent the standard from being turned, and the nut 3 isturned with another wrench to raise or lower the screw.

Obviously the hole in the standard and the head of the screw might havedierent forms from those shown, and a prism with a greater or lessnumber of sides than the prism l1 has might be substituted for thatprism.

A set consists of three jacks, one of them having the form shown inFigs. l and 2, another that shown in Figs. 3 and 4, and the other a formwhich is a mean between those shown, the screws of the jacks beinginterchangeable. The utility of a set of jacks thus constituted isgreater than that of a plurality of duplicate jacks, since it includesthat resulting from the use of jacks of different heights, or jacks ofthe same height, as circumstances may require. With such a set of jacksit is plain that an object can be readily and accurately adjusted to anyof a great number of -positions and there supported during the operationto be performed upon it.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

l. A jack-screw comprising the combination of: a hollow standardcomposed of a fiatbottomed base and a prism fixed thereon; a screwprovided with a head fitting the interior of the standard; means toprevent the screw'from turning in the standard; and a nut engaging thescrewand having a bearing on the top of the standard; substantially asdescribed.

2. A jack-screw comprising the combination of: a standard consisting ofa-base and a prism ll'and containing a square hole l2; a screw havingthe head 20 fitting the hole l2; and a nut 3 engaging the screw andhaving a bearing on the top of the standard; substantially as described.

FRANCIS H. STILLMAN.

In presence of- DAVID E. GRAHAM, EDWARD R. M. VANNETT.

